We intend to isolate auxotrophs and then to map them by parasexual and sexual genetic methods. We will use several strategies to continue to improve the technology of sexual genetic analysis. Using the defined medium, we will ask if the removal of amino acids and glucose is required for aggregation to be initiated or if the loss of each elicits a separate series of biochemical and morphological responses. Using our existing temperature-sensitive mutants affecting aggregation, we will attempt to find those points in the aggregation process at which these mutants are blocked. These mutants will be tested for structural defects in the enzymes assumed to be critical to development. We will continue to study a mutation on linkage group IV which causes rapid development and which alters cyclic AMP metabolism. We will define the effects of the mutation more precisely.